The Napa River is a river approximately 55 miles (89 km) long in the U.S. state of California. It drains a famous wine-growing region called the Napa Valley, in the mountains north of the San Francisco Bay. Milliken Creek and Mt. Veeder watersheds are a few of its many tributaries. The river mouth is at Vallejo, where the intertidal zone of fresh and salt waters flow into the Carquinez Strait and the San Pablo Bay.

Napa Valley is an American Viticultural Area (AVA) located in Napa County, California. It was established by the Bureau of Alcohol, Tobacco and Firearms (ATF) on January 27, 1981. Napa Valley is considered one of the premier wine regions in the world. Records of commercial wine production in the region date back to the nineteenth century, but premium wine production dates back only to the 1960s.